It's not an early beta. It's not even an alpha. It's a preview. Basically it's Windows 8.1 with all the new features, they could even change the UI completely for the release version.
This is an old thread about an early preview version of Windows 10. Rather than bumping an old thread you should post your own asking for help in the questions and support forum.
I am and will be a Linux user at heart (debian distros), but for Windows apps that must be run in Windows, it's Windows 7 for me. None of this Windows 10 junk, no TY. I can't run Windows 10 anyways, otherwise, how would I have a working computer to be able to type out tech support for all the poor folks that upgraded to a now-unstable Windows 10??? No, really, on-point, download WHOCRASHED (it's a program, google it), and run it on your PC and have it scan the memory dumps. It'll tell you what device driver is causing it, or it's always certain bugcheck code that could be related to something like a faulty overclock or faulty stick of ram or a dodgey mainboard. It's useful to have, and it helped me quickly find out why my video driver BSOD'ed with Beam in february. After the 2nd time in 2 weeks it crashed while I was making maps, I ran WHOCRASHED and here it was the video driver. I then updated the video driver, and 1200+ hours later not one BSOD. The machine has pretty much been on all the time since then, NO BSODs. So you could really just have a device driver bugging out Windows 10. IF you can't get to the bottom of it, revert to your older windows version and use the phone-in activation if online activation fails. EDIT: Didn't realize this was bumped, but leaving this for others to find since it's already bumped. Windows 10 and games: It doesn't support older starforce/securom etc copy-protection/DRM - buy it on STEAM or GOG.com to avoid this Windows 10 may not be compatible with your game's other required services like installing DOT.NET or something automatically via Steam, so look for what it needs and make sure it's installed.
It's been more stable for me than Win7 and XP. What? Stop spreading lies. .NET is Microsoft's software, so it's obvious that it would be fully compatible. Just about everything that is compatible with Win7 or Win8/8.1 will be compatible with Win10.
Stop with your monkey business, child. I said the INSTALLER, meaning, the script that runs the installer(s) that steam usually automatically runs when you download a game, doesn't always automatically run on windows 8 and 10. Knock it off already, and read more carefully next time. You mention everything... well many of my old games don't run due to DRM failing, so without updates from the developer, it won't run, luckily most of my library is digital now as with many people - but not everyone is that lucky. If you keep trying to hassle me you're going to find yourself very quickly grounded from the Beam forums. Behave.